The invention relates to a system and method for determining groove/land (G/L) switching points of an optical disc, and more particularly, to a system and method for determining G/L switching points of an optical disc according to a motor rotating signal and original G/L switching points.
Certain types of optical discs, such as DVD+RW optical discs, data are recorded in grooves. However, for other kinds of optical discs, such as DVD-RAM, data is recorded in both grooves and lands. Therefore, it is important for a servo system to determine grooves and lands accurately for disc such as the DVD-RAM type.
Please refer to FIG. 1. FIG. 1 shows a related art method for determining G/L switching points. U.S. Pat. No. 6,091,678 discloses a method for determining G/L switching points by utilizing an optical pick-up head signal 100 (that is, the envelope of the header field) to generate G/L switching points. As shown in FIG. 1, the rising edge and falling edge of a G/L switching point signal 102 indicates the G/L switching points. However, it is difficult to maintain the optical pick-up head signal 100 in a stable state, thus the determination of G/L switching points is usually inaccurate.
Additionally, U.S. Pat. No. 6,333,902 discloses another method for determining G/L switching points. The method includes decoding a PID (Physical Identification) and determines G/L switching points according to the 25th through 27th bits of the PID. However, this approach fails when the PID is decoded incorrectly.